Nail feeding mechanism



June 13, 1939. v G C, PAXTON 2,161,973

' NAIL FEEDING MECHANISM Filed Feb. lO, 1937' 4 Sheets-Sheet l lig-1| i 255 MI 222 45 55 v 222\ .Sfr

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.June 13, 1939. G, c. PAxToN NAIL FEEDING MECHANISM l Filed Feb. lO, 193'? '4 Sheets-Sheet 2 Ffa 2;

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Jane 13, 1939. G, PAXTON 2,161,973

NAIL FEEDING MECHANISM Filed Feb. lO, 1957 4 Sheets-Sheet 5 /M/f/Wae fPz c Para/V 'June 13, 1939. GV PAXTON 2,161,973

NAIL FEEDING MECHANISM Filed Feb. lO, 1937 4 Sheets-Sheet 4 (KMK illu! Illu" 1 Patented June 13, 1939 UNITED STATESA PATENT OFFICE Food Machinery Corporation,

San Jose, Calif.,

a corporation of Delaware Application February 10, 1937, Serial No. 125,096

18 Claims.

This invention relates to the nailing machine art and hasvparticular utility in feeding nails automatically as these are required by a nailing machine.

`It is an obiect of my invention to provide a nail feeding mechanism which is simple in conon and certain i'n its operation.

While my invention is adapted for use with a wide variety of types of nailing machines, certain features of the invention render it particulady-useful on a type of nailing machine shown in copending application, Serial No. 688,104 filed September 5, 1933, in which I am a joint app licant, the present application being a continuation in part of the aforesaid copending application. In that particular machine the nail Adrivers are fixed in the upper structure of the frame; the .nail chucks are slidably suspended about the lower ends of the drivers; and the Work 9o' is Ysupported on a nailing table which is elevated to lift'the work against the nail chucks which tre-supplied with nails prior to each nailing operation by the nail feeding mechanism of my invention,

the nailing table then continuing upward to lift the nail chucks and impale the work on the nails with the same effect as if the nails had been l'driven downwardly into the work.

It is a. further object of my invention to provide a nail feeding mechanism which is particularly adapted to operate in the feeding of nailsv to a nailing machine of the particular type above noted.

The manner of accomplishing the foregoing objects, as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying v drawings, in which: i

Fig. 1 is a front elevational view of a nailing l machine in which a preferred embodiment of my invention -is incorporated.

Fig. 2 is an enlarged sectional view taken on the line 2-2 of Fig. l.

Fig.' 3 is a sectional view taken on the line 3-3 of Fig. 2.

' Fig. 4 is a view similar to Fig. 2 with the parts thereof in different operative positions.

Fig. 5 is a perspective view of the nail feeding mechanism of my invention positioned as shown in Fig. 3.

Fig. 6 -is a perspective view of the nail feeding mechanism of my invention positioned as shown. in Fig. 4.

Fig. 7 is a fragmentary front elevational view of a nailing machine embodying the nail feeding mechanism of my invention with a modified form of hopper rocking means.

' Fig. 8 is a view similar to Fig. 3 and illustrating modified forms of the baille plate and gridiron of my linvention.

Fig. 9 is a view similar to Fig. 4 illustrating different operative positions of the aforesaid modiiied forms of baille plate and gridiron. Fig. 10 is a. cross sectional view taken on the line lil-i9 of Fig. 9 and illustrating the `modiiied form of baille plate shown therein.

Fig. 11 is a perspective view of the modified form of gridiron shown in Figs. 8 and 9.

Referring specically to the drawings and particularly to Figs. 1-6 inclusive, I have shown therein a preferred embodiment of my invention as incorporated in a lid nailing and strapping machine 35, this machine including a frame 36, an elevatorl 31, a nailing mechanism 38, and a control mechanism 40.

The frame 36 The frame 36 includes a rectangular base 4| having a heavy transverse channel iron 42 and four posts 43 which are rigidly secured to the corners of the base 4| and extend vertically upward therefrom. End pairs of the posts 43 are connected by bars 46 and spacers 41. Upper ends of side pairs of the posts.43 are connected together by relatively heavy side plates 48.

The frame 36 also includes a channel iron 58 which is supported at opposite ends on the bars 46. The channel iron 58 has an aperture formed vertically therethrough, through which a hollow standard 59 extends, the lower end of this standard resting on channel iron 42 and being welded to both the channel irons 42 and 58. Also extending between and secured at their ends to the channel irons 42 and 58 are angle iron motor struts 60.

The elevating table 37 Bolted on the motor struts 60 is an electric motor 65, this motor having a drive pinion 66 which meshes with a jack gear 61, the latter having a nut formed at the middle thereof which threadedly engages a jack screw 14 on the upper end of which is xed a nailing table 80. This nailing table is provided with rollers 8| to form a conveyor on which a box B may be received in the machine 35 a stop 82 being located on the discharge end of the nailing table to properly locate the box B thereon. 'I'he box B is conveyed to the machine 35 on a packed box conveyor 83 and after the box B has been lidded and strapped it is discharged from the machine on to a discharge conveyor 85.

The nailing mechanism plates 48 by cap screws |33 extending through.

rigidly connected yface of the cross bar |26 is a groove 205 and square nail drivers 266 have their upper ends held in place in the groove 205 by a key 201 which extends into suitable notches provided in the drivers206, the key 201 being secured in any suitable manner to the lower face of the cross bar |96.

Disposed between the side slide bars |90 is a chuck beam 206 having guide shoes 209 provided on its opposite ends, these guide shoes embracing the side slide bars |90.so as to guide the chuck beam vertically thereon. Provided on the upper edge of the chuck beam 206 at the middle of the beam is a lid' centralizer spring lug 2 I 9. Pivotally mounted on the spring hanger |99 andA on opposite ends `roi' the chuck beam 206 are telescopic spring spindles 22| on which heavy compression springs 222 are mounted under constant tension. Provided on the lower edge of the chuck beam 226 and extending inwardly is a pair of crown sheet attaching eyes 222.

Formed on the chuck beam 206 and extending inwardly across its entire length is a chuck spring supporting boss 224, chuck springs 225 being secured by screws to an inclined lower face of this boss and extending through suitable notches in the lower edge of the chuck beam 206 and downwardly on the opposite side of the chuck beam. The lower ends of the chuck springs 225 are bent to extend vertically downward and pockets 226 are Vformed in these springs, preferably by expressing the material thereof outwardly. Yieldably held against the chuck beam 206 by any suitable means is a compound spring chuck block 22|, this block having a plurality of driver guideways 222, provided thereon,v and a rearwardly exn tending boss 222 opposite each of these guideways,

this boss providing a nail feeding duct 224, leading into the channel 222 and inwardly inclined faces against which chuck springs 225 are secured by screws. 'I'hese springs are substantially identical with springs v225 and extend inwardly and downwardly to cooperate with springs 225 in the manner which will be made manifest hereinafter.

Removably supported in each of the ducts 224 and connected therewith is a nail funnel 221. Mounted on the chuck beam 208 are brackets 242, these pivotally carrying oppositelends ofv an end tucker 242 and a lid depressor and centralizar 244. The end tucker 242 comprises two substantially cylindrical bodies, one of which is disposed on the axis of rotation of the tucker and the other of which is disposed parallel with the nrst body and spaced therefrom, the two being connected with a substantiallyL continuous web of metal. After extending throughthe rearmost bracket 242, the tucker 242 has an arm 245 which extends outwardly at an angle as shown in'Fig. 3, this arm being connected by a spring 295a to the bar |96. The end tucker is thus held yieldably in its downwardmost position as shown in Figure 3, in which position it is adapted to support one anims end of a box lid L. Secured on the tucker 242 is a lid backstop 246.

'Ihe lid depressor and centraliser 244 has a cross section as shown in Figs. 3 and 4, which provides a notched lip 256 which extends inwardly therefrom. Pivotally connected to an arm A25| on the lid depressor and central'lzeris the clevis of a rod 252, the upper end of this rod extending through the lug 2|9 and carrying a spring 254, which constantly urges the'lid depressor and centralizer 244 downwardly.

Included in the nailing mechanism 26 is a pair of nail supporting and feeding units 255, one of which is associated with each of the nailing units |26 and |69. Each of the units 255 includes a nailhopper 260, having a door 26|, a rear wall 262, and side walls '262, the inner ends of the latter being pivotally connected with the hopper 262 are also connected by links 264 to the chuck beam 206, as shown in Fig. 5.

Extending from the upper edge of the rear wall 262 to spaced points in the oor 26| are the individual rods of a nail mass breaking gridiron 265. From the points where thev rods of this gridiron are secured to the iloor 26|, slots extend forwardly in this floor to a front edge 261 of the latter. Formed in the edge 261 adjacent to each of the slots 266 is a relativelysmall keeper notch 266. 'I'he hopper 266 has a fixed baille wall 269 extending between the walls 262 and rigidly secured thereto, and to the iloor 26|, there being notches provided in the lower edge of the baille wall 269, each of these notches spanning one of the slots 266 to permit nail head of nails which have dropped downwardly into the slots 266 to pass underneath the baille wall 269. Pivotally mounted between the walls 262 is a baille plate 210, this plate having a flange 21| at its upper end, and a set screw 212, the latter being adapted to engage the fixed baille wall 269 as shown in Fig. 4 to limit the downward swinging movement of the baille plate 210. Also extending between the walls 262 and in front of the fixed baille wall 269 is a rod 212 and in front of the fixed baille 'wall 269 is a rod 212 on which are pivotally mounted a series of nail traps 214, these being held in spaced relation by spacers 215. Each of the traps 214 is disposed over one of the slots 266 as shown in Figs. 5 and 6.

Referring now to Figs. 2, 3 and 4, two bracketsr 260 are connected to the lower face of the hopper floor 26| and extend forwardly beyond the front edge 261 of said floor. Slidably mounted on these brackets 260 (Figs. 3, 4 and 5) is a picker bar 26| having a pair of slots 262 through which cap screws 262 extend, these screws then screwing into suitable apertures in the brackets 222.\ Disposed between the heads of the cap screws 262 and the picker bar 26| so as to cover slots 262 are guard washers 264. Fixed on the picker bar 26| is an actuating arm 265, the extremity of which is bent as shown in Fig. 5 to extend into the upper bifurcated end of the cam lever 200 by which the picker bar 26| is adapted to be actuated. As shown in Fig. 2, a coil spring 266 attaches to one of the brackets 260 andthe picker bar 26| soas to constantly urge this picker bar into the position in which itis shown in Figs. 2 and 5.

The picker bar 26| has its lower edge disposed parallel and close to the front edge` 261 of the hopper floor 26|, and this edge of the picker bar i s provided with a series of pairs of notches, one pair for each of the slots 266 of the hopper floor. Each of these pairs of notches comprises a small transfer notch 281 and a large discharge notch 288, the notch 281 of each of these pairs being opposite one of the keeper notches 288 when the picker boris positionedas shown in Fig. 5. while the large discharge notch 288 of that pair is on the opposite side of the keeper notch 288 fromthe slot 286 adjacent that keeper notch 288. The notches 281 and 288 are spaced apart the same distance from their centers as is each of the slots 286 and the adjacent keeper notch 268.

We .havenow completed the description of the nailing unit |89. Nailing unit |88 is an exact duplicate of nailing unit |89 except that instead of ahook |85 being formed on the forward chuck beam .,stop |94,- the corresponding chuck beam s top .in nailingunit |88 merely has a shallow V-shaped lid end guide 289, as shown in Fig. 1. Suspended at its opposite ends on eyes 223 is an arched crown sheet 298.

The control mechanism 40 'rms'mecnanism mondes a switch m which is mounted upon a frame36 as shown in Fig. 1,

-this switch being controlled by a foot pedal 344 turirto'I the position in which it is shown in Fig.

1, the current is shut off from the motor 65 so that this' stops, leaving the nailing table 88 where it happens to be. When the operator releases all pressure from theA pedal 344, the spring 358 on theiink 341 lifts this link, thereby causing the switch 343 to reverse the direction of rotation of the motor 65 and causing this to rapidly draw the nailing table l88 downwardly. When the nailing .table .approaches its lowermost position, an arm 35| thereon engages an arm 352 on the shaft 345 so as to rotate the latter suiliciently to neutralize the switch 343 and shut olf the motor.

Operation In commencing the operation of the machine I5 parts thereof are positioned as shown in Fig. 1. A -box B is iirst rolled on the nailing table 88 Iior'n the conveyor 83 until the box comes to rest against the sto'p 82. A lid L is then inserted from I the I'na`chine into the position in which this is shown in iF'ig. 1, with the ends of the lid resting on the "end tuckers 243. At this time it is to be noted that the ends of the box B are located vertically beneath the end tuckers 243, the ends of the lid L, and the batteries of nail chucks in the nailing units |88 and |89. The operator now steps upon the pedal 344, causing the nailing tabie 88 to rise until the overlled fruit F therein engages the lid L and arches this upwardly against the crown sheet 298. During this upward movement the end tuckers 243 engage the fruit in the box and tuck this inwardly, and these tuckers are-then engaged by the ends of the box and rotated upwardly and outwardly allowing the lid` lends to be pressed on the box ends by the lip 2584 of the lid depressor and centralizer 244. When this is effected the upward movement of the nailingtable is transmitted positively to the box ends and lid ends through the lid depressor and centraliser so as to lift these against the lower faces ofthe chuck beams 288. Up until this point the chuck beams 288 have been held in 'their downwardmost positions by the downward pressure exerted against the chuck beams by the springs 222. The lid ends are now pressed on td the ends of the box in readiness to be nailed there, and this is etl'ected b y the chuck beams responding to the positive upward pressure of the nailing table so that these beams rise, compress-I ing springs 222 and permitting nails deposited in the guideways 232 to be held downward by the stationary nail drivers 288, thus causing the lid ends and box ends to be impaled on these nails as shown in Fig. 4 with the same eifect as if the nails had been driven down through the lid ends into the ends of the box. When the box reaches its upwardmost position as shown in Fig. 4,. the motor stalls, the operator removes his foot from the pedal 344, and the action of spring 358 causes the switch 343 to reverse the motor and draw the nailing table 88 downward until it is stopped in its downwardmost position by engagement of the arms 35| and 352 as above described.

As the nailing table returns downwardly from its upwardmost position, the parts embodied in each of the nailing units |88 and |89 return to the positions in which they are shown in Figs. l, 2 and 3.

The upward and downward reciprocation of the chuck beams 288 in each nailing operation accomplishes through the links 264 the oscillation of the nail hopper 268 between downwardly inf clined positions as shown in Figs. l, 2, 3 and 5 and upwardly inclined positions as shown in Figs. 4 and 6.

A quantity of nails N are maintained in the hopper 268, the great mass of these being retained in the back end of each of the hoppers 268 behind the bars of the gridiron 265 thereof. As the hoppers 268 are rocked upwardlyas shown in Fig. 4, the mass of these nails behind the grid 265 are hurled against the bars of this grid so that individual nails are separated from the mass and drop forwardly on to the floor 26| in front of the gridiron. A certain portion of these indid vidual nails roll into position where the body of the nail drops into one or the other of the slots 266. The nails which thus ilnd their way intol these slots hang therein by their heads, and with each upward rocking of the nail hoppers, these nails slide downwardly underneath the baille plate 218 and baille wall 269 until they eventually pass under the latches 214 by which they are retained in those portions of the slots 266 which lie adjacent to the mouths of these slots at the edge 261 of the hopper floor 26|. It is thus seen that the latches 214 lalways retain a supply of nails in the forward ends of the slots 266 in readiness to befed from these slots.

When the chuck beam 288 moves upwardly in each nailing operation, it not only tilts the hopper 268 upwardly as shown in Figs. 4 and 6, but the roller 2|3 shown in Fig. 5 engages the picker operating cam lever 288 so as to shift the picker bar 28| rearwardly into the position in which it is shown in Fig. 6. This places the transfer notches 281 of the picker bar 28| opposite the respective hopper floor slots 286 at a time when this hopper floor is inclined steeply l 288 in the hopper door edge 281. with a result which will be .explained hereinafter. The re turn movement of the picker bar to the position in which it is shown in Fig. 5 commences while the hopper'floor is still inclined upwardly from its edge 281 so that the transfer notches 281 carry. the nails fed thereinto away from in front of the slots 288, and when the picker bars 28| have 'returned to their forwardmost position as shown in Fig. 5 and the hoppers 288 have rocked downwardly as shown in that view, the nails thus removed from the slots 288 are deposited from the transfer notches 281 into the keeper notches 288.

I'he nails thus deposited in the keeper notches 288 remainthere until another rocking cycle of the nail hoppers 288 takes piace. When this occurs, the rearward movement of the picker bars 28| commences before the hoppers 288 have swung upwardly sumciently to transfer the nails in the keeper notches 288 back into the transfer notches 281. These nails thus remain in the keeper notches 288 as the picker bars 28| slide rearwardly and the hoppers 288 are rocked upwardly past the horizontal position into their upwardly inclined positions as shown in l'lg. 6. 'Ihe rearward movement of the picker bars 28| brings the large discharge notches 288 opposite the keeper notches 288 as shown in Fig. 6 so that the nails which were fed to the keeper notches during the preceding hopper rocking cycle now drop downwardly through the discharge notches 288 into the respective nail funnels 281 positioned therebeneath as shown in Fig. 4. It is thus seen that a nail is fed downwardly through a funnel 281 to each of the nail driving guideways 282 of the machine 88 so that in each nailing operation, this guideway contains a nail which will be driven therefrom by the driver 288 which slides into this guideway as the chuck beams 288 are lifted.

From the foregoing description it is evident that I have provided an extremely simple nail feeding mechanism which combines both the nail hopper and the nali feed control and in which these are operated in a very simple manner directly from the moving parts of the nailing mechanism.

Reference is now made to Figs. 8, 9, 10 and 11 which illustrate modified means for use in my invention for breaking up the mass of nails in the nail hopper and facilitate their dropping individually into the strippins slots of the hopper. 'I'hese means include modied form of gridiron 818 which, as shown in Fig. 1l, includes a shaft 81| having bars 812 welded thereto and extending downwardly in parallel relation. Opposite ends of the shaft 81| are provided with collars 818 to space the gridiron 818 relative to the side walls 288 of the hopper 288 when the extreme ends oi.' the shaft 81| are disposed rotatably in suitable holes in the side walls 288. Ihe gridiron 818 is free to swing by gravity about the shaft 81|, as the hopper 288 is rocked upwardly, until the lower ends of the bars 812 engage the bottom 28| of the hopper. This limited position to which the gridiron 818 rocks as the hopper is lifted is shown in Fig. 9, where it is seen that the nails have fallen inwardly and downwardly against the bars 812 with the result that individual nails separate themselves from the mass which gravitate downwardly on to the floor t 28|, so that a certain portion of these fall into the slots 288.

In Figs. 8, 9 and 10 I also show a modified stantialiy like the swinging baile plate 218 previ- Olisly described but which llcks a' M me'.

212, the plate 888 being slightly lngerthln the plate 218 so that the lower edge 88| thereof engages the hopper bottom 28| to limit the swinging movement of the balle plate 888 in response to the upward rocking of the hopper 288. The lower edge 88| of the baile plate 888 is provided with notches 882, one of these being located over each of the slots 288, these notches providing free spaces when the edge 88| of this plate is resting against the door 28|, through which the heads of nails may pass to permit the nails hanging in the slots 288 to slide downwardly beneath the baille plate 888 when the hopper 288 is in upwardmost position as shown in Fig. 9.

The mounting of the baille plate 888 so as to swing free of the floor 28| when the hopper 288 is in downwardmost position causes all the nailswhich might have become engaged with the lower edge of this plate to be freed to gravitate downwardly. Furthermore the freedom of the gridiron 818 to swing as shownin Fig. 8 when the hopper is down, permits all the nails thus gravitating rearwardly in the hopper to pass underneath the gridiron 818 into 'the mass of nails confined in the rear portion of the hopper. This accomplishes a cleaning out of all places where the nails might stick in the hopper each time the hopper returns to downward position, and assures that in the next upward rocking movement of the hopper, what nails there are in the hopper besides tho which have already dropped into the slots 288, will have to be sifted through the gridiron 818 in order to again appear on the floor 28| of the hopper between the baille plate 888 and the gridiron 818. It is to be noted that the bars 812 are equal in number and are spaced equally with the slots 288 so that what nails are thrown between the bars. with the upward swing' of the hopper, land on the iioor in between the slots 288 so as not to interfere with the tendency of nails lying near these slots to roll into the slots.

Referring now to Fig. 7, I have shown herein a modified form of means for rocking the nail hoppers 288. Each of these means comprises a telescopic link 888 and includes a rod 888 which is flattened at its upper end and pivotally connected to the hopper 288 which it is to operate. The rod 888 has a collar 881 adjustably secured thereon, the collar having a linger 888 which extends outwardly so as to extend under the frame plate 88 on that side of the machine. 'Ihe lower end of the rod 888 extends through a collar 888 which is pivotally mounted by a pin 888 on nailing table 88 of the machine 88. Coiled about the rod 888 between the collars 881 andv 888 is an expansion spring 88|. Fixed adiustably upon the rod 888 below the collar 888 is a stop collar 888. When equipped with links 888 for operating the hoppers 288, the machine 88 of my invention operates in a similar manner to that already described, excepting that the upward swinging of the nail hoppers 288 starts as soon as the elevation of the nailing table 88 commences. 'Ihe collar 881 is so adjusted on the rod .888 as to engage the lower edge of the frame plate 48 thereabove, when the hopper 288 has been rocked upwardly to the proper upwardly `inclined position. During the balance of the upward movement of the nailing table therefore, the collar 888 merely compresses the spring 88|, but does not. impart any further elevation to the link ill. One of the advantages of the link l" is that a much slower upward rocking movement may be imparted to the hoppers Ill by the use of these links than by the use of the links 2, the lower ends of which are pivoted to the chuck beams 208. 'I'his is desirable as where the nailing operation is performed speedily, the chuck beams 208 rise with such speed as to flip the nails from the hopper 280 when this stops in its upward position.

What I claim is:

l. In a nail feeding mechanism, the combination of: a nail hopper having a rear wall, side walls, and a floor, there being'a slot formed in said oor having a mouth at the front edge of said floor, there being a keeper notch in said edge adjacent the mouth of said slot; means for rocking said hopper about an axis parallel to said edge between positions inclined upwardly and inclined downwardly from said edge; a nail picker bar mounted adjacent said edge and shiftable between nail receiving and nail transferring positions, there being a Asmall transfer notch and a relatively large discharge notch in said picker bar, said transfer notch being opposite said mouth and said discharge notch being opposite said keeper notch when said picker bar is in nail receiving position, said bar being in this position when the hopper is inclined upwardly from said edge, said transfer notch being opposite said keeper notch when said hopper is inclined downwardly from said edge and said picker bar is in nail transferring position; and means for coordinately actuating said hopper and picker bar as aforesaid. l

2. A combination as in claim l in which a latch means is provided on said hopper to prevent the nails disposed in said slot close to said mouth from sliding back said slot towards the rear end of said hopper when said hopper is inclined downwardly from said edge.

3. In a nail feeding mechanism, the combination of: a. nail hopper having a fioor with a stripper slot therein, said slot having a mouth at a given edge of said door; means for pivotally mounting said hopper on an axis parallel to said edge; a picker bar shiftably mounted on said hopper adjacent said edge of said floor; means for rocking said hopper between positions in which said floor is inclined upwardly and then downwardly relative to said edge; and means for actuating said picker bar coordinately with ythe hopper to receive a nail from said mouth in Ithe first of said positions, isolate said nail temporarily while said hopper is in the second of its positions, and discharge said nail upon said hopper returning again to the flrst of said positions.

4. In a. nail feeding mechanism the combination of: a nail hopper having a floor with 'a stripper slot therein, said slot having a mouth at a given edge of said oor; means for pivotally mounting said hopper on an axis parallel to said edge; means for rocking said hopper between positions in which said floor is inclined upwardly and then downwardly relative to said edge; and feed control means slidably disposed adjacent said edge opposite the mouth of said slot and operating to receive a nail from said mouth during each such rocking cycle and during each such cycle to drop a nail so received, said receiving and dropping functions both taking place when said hopper is inclined upwardly from said edge.

5. A combination as in claim 4 in which said feed control means is mounted on said hopper.

6. A combination as in claim 4 in which the nail dropped during each rocking;V cycle is the nail received during the cycle immediately pref ceding.

7. A combination as in claim 4 in whichlaid feed control means is mounted on said hopper and in which the nail dropped during each rocking cycle is the nail received during the cycle immediately preceding. v

8. In a nailing machine the combination of a table for supporting the work; a nailing unit including a nail driving bar, a plurality ofl drivers thereon; a plurality of chucks suspended about the lower ends of said drivers and slidable relative to the latter, and a chuck beam for uniting said chucks; means for causing relative vertical movement between said table and said unit to bring said chuck beam and work into engagement and cause said chuck beam to slide relative to said drivers and cause nails to thus be driven into said work; a nail hopper having a oor with stripper slots therein, said slots having mouths at a given edge of said floor; means for pivotally mounting said hopper on an axis parallel to said edge thereof; link means pivotally connected to said hopper and to said nailing table for rocking said hopper about said axis between positions in which said iloor is inclined upwardly and then downwardly relative to said edge; and means for controlling the delivery of nails from the mouths of said slots to said chucks.

9. In a nailing machine the combination of: a table for supporting the work; a nailing unit including a nail driving bar, a plurality of drivers thereon; a plurality of chucks suspended to receive the lower ends of said drivers and slidable relative to the latter, and a chuck vbeam for uniting said chucks; means for causing relative vertical movement between said table and said unit to bring said chuck beam and work into engagement and cause said ch-uck beam to slide relative to said drivers and cause nails to thus be driven into said work; a nail hopper having a. floor with stripper slots thereon, said slots having mouths at a given edge of said iloor; means for pivotally mounting said hopper on an axis parallel to said edge thereof; link means pivotally connected to said hopper and to said nailing table for rocking said hopper about said axis between positions in which said floor is inclined upwardly and then downwardly relative to said edge; lost motion means to limit the rocking movement which may be imparted by said link means to said hopper, said lost motion means absorbing the excess relative movement between said hopper and said nailing table following the coming into operation of said limit means; and means for controlling the delivery of nails from the mouths of said slots to said chucks.

10. In a nail feeding mechanism, the combination of: a nail hopper having a iioor with a series of stripper slots therein, said slots having mouths at a. given edge of said floor; means for pivotally mounting said hopper on an axis parallel to said edge; means for rocking said hopper between positions in which said floor is inclined upwardly and then downwardly relative to said edge; means for controlling the delivery of nails from said mouths during each rocking cycle;

means in said hopper for obstructing the movement of nails downwardly therein when said iioor is inclined upwardly relative to said edge excepting for those nails which have dropped downwardly into said slots with their heads lying just above said slots; and a gridiron pivotally IIJ mounted on said hopper to hang downwardly therein and be rotated by gravity as the hopper rocks as aforesaid. the rotation of said gridiron being limited -to cause it to obstruct at spaced points the downward movement of a mass of nails contained in said hopper thereby causing individual nails to be detached from said mass and deposited on said door beyond said gridiron.

11. In a nail feeding mechanism the combination of: a nail hopper having a door with a stripper slot therein, said slot having a mouth at a give edge of said floor; means for pivotally mounting said hopper on an axis parallel to said edge; means for periodically rocking said hopper between positions in which said floor is inclined upwardly and then downwardly relative to said edge; barrier means for confining the bulk of a mass of nails placed in said hopper at the opposite end thereof from said edge but permitting individual nails to break away from said mass and fall onto said floor when said iioor is inclined upwardly, certain of the nails thus breaklng away droppins into said slot; a second barrier means disposed between said rlrst barrier means and the aforesaid edge oi said floor. said second barrier means preventing gravitation past it of any nails excepting those which have dropped into said slot; trap means disposed between said second barrier means andsaid edge of said floor, said trap means preventing the return towards said second barrier means of nails which already have gravitated past said trap means when said floor is inclined upwardly from said edge; `and means for receiving nails from said mouth of said slot when said floor is inclined upwardly.

l2. A combination as in claim 11, in which said first barrier means is pivotally suspended insaidhoppersoastoswing free fromsaidiioor when the latter is inclined downwardly from said edge, permitting nails which have gravitated downwardly through said first barrier means when said iioor is inclined upwardly from said edge and which nails have not dropped into said slot, to gravitate beneath and behind said ilrst barrier lmeans so as to be confined therebehind when said hopper again rocks to incline said iioor upwardly relative to said edge.

13. A combination as in claim 11. in which said second barrier means is pivotally suspended on said hopper so that when the floor of the latter is inclined downwardly from said edge said second barrier means swings free from the iioor to permit any nails caught thereunder to gravitate downwardly to rejoin the aforesaid mass of nails.

14. A combination as in claim 1l, in which both said barrier means are pivotally suspended on said hopper so as to swing clear of the floor of said hopper when the latter is inclined downwardly relative to said edge.

15. In a nail feeding mechanism the combination of: a'nail hopper having a iioor with a stripper slot therein, said slot having a mouth at a given edge of said door; means for pivotally mounting said hopper on an axis parallel to said edge; means for periodically rocking said hopper between positions in which said floor is inclined upwardly and then downwardly relative to said edge; barrier means confining the bulk of a mass of nails placed in said hopper at the opposite end thereof from said edge but permitting individual nails to break away from said mass and fall onto said floor when said floor is inclined upwardly from said edge. certain of the nails thus breaking away dropping into said slot; a second barrier means disposed between said first barrier means and the aforesaid edge of said door, said second barrier means preventing gravitation past it of any nails 'excepting those which have dropped into said slot, said second barrier means being pivotally suspended from said hopper so as to hang clear of said floor when said hopper has been rocked to bring said floor into its'downwardly inclined position aforesaid; and means for receiving nails from said mouth of said slot when said' floor is inclined upwardly as aforesaid.

16. In a nail feeding mechanism the combination of: a nail hopper having a door with a series of stripper slots therein, said slots having mouths at a given edge of said door; means for pivotally mounting said hopper on an axis parallel to said edge; 4means for rocking said hopper between positions in which said iloor is inclined upwardly and then downwardly relative to said edge; a gridiron comprising a body and a series of dngers extending rake-like downwardly from said body, said gridiron body being pivotally mounted on said hopper to permit said fingers to hang downwardly therefrom, said gridiron being rotated by gravity as the hopper rocks to cause said fingers to swing free of said floor when the latter is inclined downwardly as aforesaid, rotation of said gridiron being limited however to cause the latter to obstruct d``wnward movement of a mass of nails contained in said hopper when said floor is inclined upwardly as aio esaid. thereby causing individual nails to be de ched from said mass and be deposited on said floor below said gridiron; barrier means disposed between said gridiron and the aforesaid edge of said floor, said ban-ier means preventing gravitation past it of any nails excepting those which have dropped into said slots and means for receiving nails from said mouths of said slotsv when said floor is inclined upwardly as aforesaid.

17. A combination as in claim 15, in which said second barrier means comprises a plate having means for limiting the rotation thereof 'about its pivotal axis when said hopper rocks to incline the oor thereof upwardLv, the lower edge of said plate when its rotation about its pivotal axis is thus limited. lying close to said oor where said plate is disposed over said s lot so as to permit the heads of nails which have dropped into said slot behind said plate to slide downwardly along said slot beneath said plate while said floor is thus inclined upwardly.

18. A combination asin claim 16, in which said barrier means comprises a plate which is' pivotally suspended from said hopper andv which has means for limiting the rotation thereof about its pivotal axis when said hopper rocks to incline the floor thereof upwardly, the lowerI edge of said plate when its rotation about its pivotal axis is thus limited, lying close to said floor where said plate is disposed over said slots so as to permit the heads of nails, which have dropped into said slots behind said plate, to slide downwardly along said slots beneath said plate while said iioor is thus inclined upwardly.

GERALD C. PAXTON. 

